Watch the ominous ad about the Newtown anniversary

A gun control group will air an ominous ad to mark the one-year anniversary of the Newtown, Conn., school shooting.Sponsored by Moms Demand Action for Gun Sense in America and Mayors Against Illegal Guns, the 30-second version of the ad shows school workers and students bowing their heads for a moment of silence.As a clock ticks, the ad shows a person carrying a duffel bag full of guns toward the school."On Dec. 14, we'll have a moment of silence for …